Field
The present disclosure relates to the deposition of nanoparticles on substrates, and, more particularly, to the deposition of nanoparticles on electrically non-conductive substrates including the formation of bonds between the nanoparticles and substrates.
Background
There has been broad scientific and technical interest in producing nanostructured composite material systems that exploit the unique properties of nanoparticles in engineering applications. The selective and intelligent integration of nanoparticles by hybridizing with various substrates enables the ability to form local multi-scale architectures for the tailoring of both mechanical and physical properties such as mechanical strength, electrical conductivity, or thermal conductivity of the nanoparticle-substrate combination.
For example, the direct hybridization where nanoparticles fully penetrate the fiber bundles of a textile, the textile forming the substrate, may be utilized as conductors for integrating sensors into the textile.
Advanced fiber-reinforced composites, such as carbon fiber reinforced polymer (CFRP) and glass fiber reinforced polymer (GFRP) composites may offer improved in-plane tensile properties for their equivalent weight in comparison with traditional metallic materials. However, Advanced fiber-reinforced composites may exhibit poor through-thickness strength and toughness properties. Previous efforts to improve the through-thickness properties of Advanced fiber-reinforced composites, for example, have examined the addition of nanoparticles such as carbon nanotubes to a substrate comprising carbon fibers. Carbon nanotubes offer high strength and stiffness on a sub-micron scale and, therefore are potential candidates to be used to modify the interstitial regions between the carbon fibers where the polymer matrix dominates the composite strength and toughness properties.
Chemical vapor deposition processes have been used for incorporating carbon nanotubes into CFRP composites by growing CNTs directly upon the reinforcing fiber using chemical vapor deposition prior to resin infusion. The chemical vapor deposition process enables carbon nanotubes to be grown at high coverage, leading to high-effective volume fraction of the carbon nanotubes in the matrix.
Chemical vapor deposition processes may cause a reduction in the strength of the carbon fibers as well as of various non-conductive fibers, and, therefore, compromise the tensile properties. For example, chemical vapor deposition may remove sizing(s) disposed about the surface of the fibers that prevent stress corrosion cracking of the fibers or that confer ultra violet light (UV light) protection to the fibers. Removal of the sizing(s) may accordingly degrade the mechanical and physical properties of the fibers, for example, due to increased stress corrosion cracking or degradation by UV light. While the chemical vapor deposition process may be scalable, the high temperatures that may be employed for chemical vapor deposition, for example, between 600° C. and 1,000° C., makes the chemical vapor deposition process energy intensive. The chemical vapor deposition process may also be less amenable to the control of carbon nanotubes purity and manipulation of surface chemistry and adhesion of the carbon nanotubes to the surface of the substrate. Furthermore, the high temperatures of the chemical vapor deposition process may make this process inapplicable to various electrically non-conductive substrates.
Dispersion/infusion approaches have been used for incorporating carbon nanotubes into CFRP composites by inclusion of the CNT within the polymer matrix. CNT volume fraction may be limited to be generally less than 1% because processing high carbon nanotubes volumes in the polymer may be difficult due to factors such as viscosity increases, fabric filtering effects, and adequate dispersion.
Accordingly, there is a need for improved processes as well as related apparatus and compositions of matter that incorporate nanoparticles with various substrates including electrically non-conductive substrates.